Thank you to all for your rapid answer.

@Amster
I saw the fuse in Mouser website, I think the same one is the following:

http://www.mouser.it/ProductDetail/Littelfuse/0875200MXEP/?qs=%2Fha2pyFadugxaz6Ka1QIzhvtD8HnMnU0Sbd%2Fe9cxA257in2%2FbECi0w==

I also called they and they told me that only after I will put the order they check the real availability in the various site they have and if present they send me, but if not present I have to wait 10 Week as this is the Factory Lead Time.
And more of this the shipping will cost 20€, so a total of 39,80€ for 10 little fuse I think is too much.

@Nca78

I think I will go for the one you suggest. It's cheap, with free shipping and it seems not to big to don't fit in the board.

Now I will have to wait about 1 month before all parts arrive, then I will let you know if fuse will fit or not.

Thank you again for your attention and a big hello from Italy.

@TimO

Thank you very much for your help, now I succesfully connected my iboard card as LAN Gateway without doing any HW modification and even any software modification to any library, simply using the sketch you sent here.

For general information to other people that want to use the iboard card with Domoticz, to avoid any problem like the following:

2016-12-18 12:06:40.840 MySensors: trying to connect to: 192.168.1.133:5603
2016-12-18 12:06:41.841 MySensors: connected to: 192.168.1.133:5603
2016-12-18 12:06:45.841 MySensors: Connection reset!
2016-12-18 12:06:45.842 TCP: Reconnecting in 30 seconds...

Consider to use the Arduino IDE 1.6.8 to compile and upload the sketch, otherwise, with newest Arduino IDE you will get the error messages above.

Thank you again for you help and a big hello to all the members of the forum.

Regards